In the conventional oscillating mechanism of an electric fan, the speed reduction mechanism is driven by the motor of the fan blade and is connected to one end of a connecting rod while the other end of the connecting rod is connected to the fan casing or base. In this way, the conventional oscillating mechanism of an electric fan is driven indirectly by the fan motor in order to oscillate.
Please refer to FIG. 1, which schematically shows the conventional oscillating mechanism of an electric fan. As shown in FIG. 1, a worm gear 111 meshed with a worm wheel 12 is disposed at the tail end of a primary driving shaft 11 of the fan. A reduction gear unit formed by two gears 13 and 14 is operatively coupled to the lower end of the worm wheel 12. The gear 14 has a shaft 15 connected pivotally to one end of a crank plate 16. The other end of the crank plate 16 is connected pivotally to one end of a connecting rod 17. The other end of the connecting rod 17 is connected pivotally to a driving element 171 received in a slot 181 of the casing 18.
The operation of the afore-mentioned conventional oscillating mechanism will be described as follows. Firstly, the fan rotates and the primary driving shaft 11 of the fan drives a speed reduction mechanism formed by the worm gear 111, the worm wheel 12, and the gears 13 and 14 of the reduction gear unit. Then, the shaft 15 of the gear 14 moves the crank plate 16, which indirectly moves the connecting rod 17. Finally, the driving element 171 moves the casing 18 in order to oscillate.
However, the oscillation angle of the conventional oscillating mechanism can not be adjusted. If an external force is imposed to vary the oscillation angle of oscillation, potential risks might occur, such as the collapse of the gear tooth, or fracture of the connecting rod or driving elements.
This “Discussion of the Background” section is provided for background information only. The statements in this “Discussion of the Background” are not an admission that the subject matter disclosed in this “Discussion of the Background” section constitutes prior art to the present disclosure, and no part of this “Discussion of the Background” section may be used as an admission that any part of this application, including this “Discussion of the Background” section, constitutes prior art to the present disclosure.